Quoting a poem by the founder of Communist China Mao Zedong, China's government said on Wednesday that the efforts by Hong Kong and Taiwan independence supporters to link up were doomed to fail, as they would be dashed to the ground like flies.

Chinese leaders are increasingly concerned about a fledgling independence movement in the former British colony of Hong Kong, which returned to mainland rule in 1997 with a promise of autonomy, and recent protests in the city.

China is also deeply suspicious of Taiwan President Tsai Ing-wen, elected earlier this year, who Beijing suspects is pushing for the self-ruled island's independence.

She says she wants peace with China, which considers the island an unruly, breakaway province.

Beijing has already warned about independence activists in both places linking up - Hong Kong activists have visited Taiwan this year - and went further at a routine news conference by China's policy-making Taiwan Affairs Office.